Re-Evaluating Botryosphaeriales: Ancestral State Reconstructions of Selected Characters and Evolution of Nutritional Modes

Abstract

Botryosphaeriales (Dothideomycetes, Ascomycota) occur in a wide range of habitats as endophytes, saprobes, and pathogens. The order Botryosphaeriales has not been subjected to evaluation since 2019 by Phillips and co-authors using phylogenetic and evolutionary analyses. Subsequently, many studies introduced novel taxa into the order and revised several families separately. In addition, no ancestral character studies have been conducted for this order. Therefore, in this study, we re-evaluated the character evolution and taxonomic placements of Botryosphaeriales species based on ancestral character evolution, divergence time estimation, and phylogenetic relationships, including all the novel taxa that have been introduced so far. Maximum likelihood, maximum parsimony, and Bayesian inference analyses were conducted on a combined LSU and ITS sequence alignment. Ancestral state reconstruction was carried out for conidial colour, septation, and nutritional mode. Divergence times estimates revealed that Botryosphaeriales originated around 109 Mya in the early epoch of the Cretaceous period. All six families in Botryosphaeriales evolved in the late epoch of the Cretaceous period (66–100 Mya), during which Angiosperms also appeared, rapidly diversified and became dominant on land. Families of Botryosphaeriales diversified during the Paleogene and Neogene periods in the Cenozoic era. The order comprises the families Aplosporellaceae, Botryosphaeriaceae, Melanopsaceae, Phyllostictaceae, Planistromellaceae and Saccharataceae. Furthermore, current study assessed two hypotheses; the first one being “All Botryosphaeriales species originated as endophytes and then switched into saprobes when their hosts died or into pathogens when their hosts were under stress”; the second hypothesis states that “There is a link between the conidial colour and nutritional mode in botryosphaerialean taxa”. Ancestral state reconstruction and nutritional mode analyses revealed a pathogenic/saprobic nutritional mode as the ancestral character. However, we could not provide strong evidence for the first hypothesis mainly due to the significantly low number of studies reporting the endophytic botryosphaerialean taxa. Results also showed that hyaline and aseptate conidia were ancestral characters in Botryosphaeriales and supported the relationship between conidial pigmentation and the pathogenicity of Botryosphaeriales species.

Morphology and molecular analyses reveal three new species of Botryosphaeriales isolated from diseased plant branches in China

“… aplosporum and Ph. rhoinum are both pathogenic ( Rathnayaka et al 2023 ). The phylogenetic state analysis of the trophic pattern, conidial colour, and separation of Botryosphaeriales conducted by Rathnayaka et al (2023) indicate that this may correspond to nutritional mode.…”

Refined Evolutionary Trees Through an Exceptionally Compatible Alignment-Substitution Model

“…Similarly, the neighborhood joining (NJ) method, which is computationally efficient for handling massive datasets, generates a phylogenetic tree from the distance matrix of the mutual dissimilarities among the sequences [49,50]. On the other hand, ML predicts the evolutionary tree with the highest likelihood score to explain the given sequence data, assuming a probabilistic model of sequence evolution [50][51][52]. Due to its simplicity, MP is only effective for smaller sequence datasets, evolving under a very simple evolutionary model, and does not consider the variance in substitution rates across different sites.…”

Seasonal dynamics of endophytic fungal diversity Grevillea robusta (Silver oak) trees

“…Lactophenol and blue cotton staining solutions were used for the purposes of microscopic examination and evaluation of fungal spores without hyaline pigment, focusing on features such as shape, color, isolation and the presence or absence of specialized appendages on the spores [20,21].…”